Antivenom injection contains preformed antibodies while polio drops that are administered into the body contain:

Answer: Attenuated pathogens
An attenuated vaccine is a vaccine created by reducing the virulence of apathogen, but still keeping it viable (or "live"). Attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent. These vaccines contrast to those produced by "killing" the virus (inactivated vaccine).

Antivenom Injection

Antivenom, also known as antivenin, venom antiserum and antivenom immunoglobulin, is a medication made from antibodies which is used to treat certain venomous bites and stings. They are only recommended if there is significant toxicity or a high risk of toxicity. The specific antivenom needed depends on the species involved. It is given by injection.
Antivenom was first developed in the late 1800s and came into common use in the 1950s. They are on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Depending on the type the wholesale cost in the developing world is 9.00 to 118.80 USD per vial. In the United States the wholesale cost is as high as 2,300 USD per dose